The average weighted market price (HOEP) for yesterday's 36,350MWh of wind production  was $13.77/MWh. If the average contract value for wind is $125/MWh, the loss is about $4 million.
There were no hours where the wind production exceeded net export levels
recent post I noted issues from the previous weekend; a quick comparison of the changes in generation, and exports, between Sundays May 5th and 12th indicates the impact of the wind production
To compensate for the additional wind generation, the system responded by increasing exports and dumping hydro.
|The gap between the two lines reflects higher demand early on the 12th|
It is apparent that during this day, increased wind that could not be dumped on export markets displaced hydroelectric generation
|Figure 3 from The Market Value of Variable Renewables|
In The Market Value of Variable Renewables Lion Hirth, writing for Vattenfall, demonstrates the falling value of vRES supply under different scenarios. Hirth looks at Europe where, unlike in Ontario, apparently wind resource had a positive correlation to demand - so the first wind turbines produced output during periods of higher demand and therefore initially wind production had higher-than-average value. Hirth measures the value of wind output using a percentage of the average price received on markets for wind output, over a period of time, as a percentage of the average market price over that time.
The more varaiable renewable energy supply increases, the more the relative value of vRES supply declines.
Hirth Figure 7 re: France)
I've pulled annual figures for wind production, total Ontario production, average rate (HOEP) for wind output and the average annual HOEP to produce measurements, comparable to those in the Hirth study, for Ontario.
The value of wind production in Ontario is eroding rapidly.
The spreadsheet for this post is here
 This is only the production on the IESO's radar, and does not include the 'embedded' wind generation, which would likely add another ~15% to the wind total.
Embedded generation is shown as decreased demand in the IESO's inadequate reporting.
 Ontario demand is reported by the IESO in a format available to the public only on Friday afternoons - in order to compare using the same data sets, the "ON Demand" in this exercise is the sum of the generation in the IESO's Output & Capability Report plus the import/export totals from the intertie reports (these do not match perfectly to the weekly IESO's historical data files - for known reasons I won't cover here)